The Government of Ireland Act provided for the appointment of the Executive Committee of the Privy Council by the Governor.[4] No parliamentary vote was required. Nor, theoretically, was the Executive Committee and its prime minister responsible to the House of Commons of Northern Ireland. In reality the Governor chose the leader of the party with a majority in the House to form a government. On each occasion this was the leader of the Ulster Unionist Party, such was the UUP's electoral dominance using both a simple plurality and for the first two elections, a proportional electoral system. All Prime Ministers of Northern Ireland were members of the Orange Order.

^The new office of Governor had not yet come into being because its creation required an amendment to the original Act. The Lord Lieutenant of Ireland had originally been granted the role and exercised the powers, functions and duties pending the creation of governor's post in 1922. Ward, p.116.